Materials Data on LaFe5H7 by Materials Project

Abstract

LaFe5H7 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. La is bonded to twelve H atoms to form LaH12 cuboctahedra that share corners with six equivalent LaH12 cuboctahedra, corners with six equivalent FeH4 trigonal pyramids, edges with three equivalent FeH4 tetrahedra, edges with six equivalent FeH4 trigonal pyramids, and faces with two equivalent LaH12 cuboctahedra. There are a spread of La–H bond distances ranging from 2.48–2.84 Å. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded to four H atoms to form FeH4 trigonal pyramids that share corners with two equivalent LaH12 cuboctahedra, corners with two equivalent FeH4 tetrahedra, corners with four equivalent FeH4 trigonal pyramids, and edges with two equivalent LaH12 cuboctahedra. There is two shorter (1.73 Å) and two longer (1.74 Å) Fe–H bond length. In the second Fe site, Fe is bonded in a 3-coordinate geometry to four H atoms. There is three shorter (1.71 Å) and one longer (2.12 Å) Fe–H bond length. In the third Fe site, Fe is bonded to four H atoms to form FeH4 tetrahedra that share corners with six equivalent FeH4 trigonal pyramids and edges with three equivalent LaH12 cuboctahedra. There is three shorter (1.71 Å) and one longer (1.83 Å) Fe–H bond length. There are three inequivalent H sites. In the first H site, H is bonded to two equivalent La and two equivalent Fe atoms to form distorted HLa2Fe2 tetrahedra that share corners with eight equivalent HLa2Fe2 tetrahedra, corners with two equivalent HFe5 trigonal bipyramids, and edges with two equivalent HLa2Fe2 tetrahedra. In the second H site, H is bonded to five Fe atoms to form corner-sharing HFe5 trigonal bipyramids. In the third H site, H is bonded in a 3-coordinate geometry to two equivalent La and three Fe atoms.